change up

change up (third-person singular simple present changes up, present participle changing up, simple past and past participle changed up)

1. (intransitive, baseball) To throw a pitch at a much slower than expected speed.

   He changed up on Wilson after three fastballs and struck him out.

2. (intransitive) To confuse someone by doing something unexpected or in an unexpected way.

   I thought that we were going to study the project some more, but then he came back from the weekend and changed up, making it a top priority.

3. to change to a higher gear in a vehicle